cudaPackages: undo the cudaPackages_11_3 fallback

...for cupy and librealsense; this commit is within the process of
stabilizing after the gcc10->gcc11 bump

pkgs/top-level/all-packages.nix

@@ -3582,7 +3582,6 @@ with pkgs;
   gpu-burn = callPackage ../applications/misc/gpu-burn {
     # gpu-burn doesn't build on gcc11. CUDA 11.3 is the last version to use
     # pre-gcc11, in particular gcc9.
-    cudatoolkit = cudaPackages_11_3.cudatoolkit;
     stdenv = gcc9Stdenv;
   };
 
@@ -23108,7 +23107,6 @@ with pkgs;
     cudaSupport = true;
     # librealsenseWithCuda doesn't build on gcc11. CUDA 11.3 is the last version
     # to use pre-gcc11, in particular gcc9.
-    cudaPackages = cudaPackages_11_3;
     stdenv = gcc9Stdenv;
   };
 

pkgs/top-level/python-packages.nix

@@ -1958,11 +1958,7 @@ in {
 
   cufflinks = callPackage ../development/python-modules/cufflinks { };
 
-  cupy = callPackage ../development/python-modules/cupy {
-    # cupy doesn't build on gcc11. CUDA 11.3 is the last version to use
-    # pre-gcc11, in particular gcc9.
-    cudaPackages = pkgs.cudaPackages_11_3;
-  };
+  cupy = callPackage ../development/python-modules/cupy { };
 
   curio = callPackage ../development/python-modules/curio { };